I met a girl for two days and chatted on WeChat. She changed from typing to pronunciation. What does this mean?

Knowing a girl for two days, starting typing and chatting, and sending voice messages slowly may indicate that she has some trust and closeness to you and is willing to communicate with you further. This may also mean that she feels that she has established enough mutual trust with you, and she doesn't need to express herself through words, but wants to communicate with you more directly.

But it may be that girls just feel convenient or lazy, don't want to type or have no patience to input slowly, or they may have confidence in their own phonetic content and feel that they can use the language freely.

So you can't say for sure that it needs to be judged by other circumstances, such as whether she has a good impression on you, whether there is a spark between you and so on. And you need to know her interpersonal relationship, behavior and tone and performance in text chat.